Lens-temperature equalizer.



v"To: all'fwhom 'Zt mayl concern c VEqualizers,

WALTEBIQTREDDEY, or sAN FRANCISCO, CALIFORNIA.

' Be it known 'that I, WALTER G. PREDDEY, a citizen .of the United States, residing at San Francisco, inz the'county of San Francisco "and State of California, have invented certain 'new and useful Improvements in Lens-Temperature Equalizers, of which the following is a specification;

useful improvements inlens temperature and particularly for equalizing the' temperature of that class of lenses in which a high temperature light is projected through 'the same;` such lenses as now cominnly used in. stereoptieon and moving picture machines.- l

This invention has for its object primarily, toprovide a lens temperature equal-A izer of the above description which will keep the temperature, at all part-s of a lens uniform whensaid lens is rising from atmosoutside surface of pherio temperature to running temperature, and cooling from running temperature to atmospheric temperature. 2,5

A. further object is to provide a lens teniperature equalizer which will b'e convenientto install, simple in construction and readily assembled.

` .'With these ends in view my invention consists in the details of construction and .combination of elements hereinafter set forth, and then specifically designated by the claims. y a

Itsvconstruction and operation' will be described in detail, referring by numerals to the accompanying drawings forininga part of this specification, and in which similar numerals of reference designate corresponding parts in all gures. l,

In the accompanying drawings :-l3`igure 1, is a broken front elevation of the lens temperature equalizer containing an ordinary lens. Fig.` 2, is an enlarged fragmentary central vertical transverse crossy sec'- tion of Fig. 1.

Referring to the drawings, 1 indicates a lens housing which may be made of any suitable heat 'conducting'and heat retaining material, such as brass or copper, and which may be'of any Vgiven size, shape or proportions. 'A nonconductor ofv heat 2 such as asbestos is shown covering a portion of the the lens housing 1. An ordinary lens 3 is shown encircled by the lens housing 1. A ring' 4. loosely-iitting inside of the lens housing 1,'fornis-an out- -the saine.

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I Specification of Letters llatent. l Patented Sept.. 22, 191ML. .ippiication sied March v24, i914. sensi No'. 826,912.

ward limiting position for lens 3 and keeps said lens in 'its proper position against the convex flange forming a part of the lens housing 1. A plurality of holes 5 are shown drilled through the lens -housing 1 and the heat insulating material 2, and is a means by which the lens-housing 1 may be attached to an ordinary lens holder of a stereopticon loi' moving picture machine. A plurality of screws 6 screw-threaded into the lens housheads of said screws, said springs forcing in on the washers S which in turn forces in the ring t and effects a constant pressure of the lens housing 1. and the ring 4 on the surface of the lexis 3.

Heretoforel, it has been the experience when projecting a high temperature light through an ordinary lens, and particularly 'in turning on and turning off said light,

that the lens will frequently crack, which is caused by the outer edge which is of a inuch smaller cross section than the center portion, cooling oil more rapidly than the center, thus eifecting ,undue tension of said len's which causes the rupture of the same.

rlhe operation of this device will then be as followsz'lt is obvious that in projecting a light of. high temperature through a lens ling 1, and compression springs 7 under the I contained by my improved lens temperature equalizer, that the thin edge of said lens will be relieved of its excessof heat over the centerr or thicker portion of the same, by the conduction of vheat from said thin edge of said lens to the lens housing 1. The lens housing 1 should be constructed so as to be of greater proportions than the lens contained therein, so that said lens will absorb more heat iii a given time than said housing 1, this being thel case the lens housing 1 will conduct the heat from the thin edge of said lens, and thus equalize the temperature of It is evident then that after the lens housing 1 and the lens 3 have been in operation for a uniform temperature, then if the light. is turned oit', the lens housing l beingy of greater .volume will retain its heat longertime that both will be of' center portion of the' same while cooling,

thus eolualizing.; the temperature of all parts of said lens.' The nonconductor lof heat-2 covering a portion of the .housing` 1 is to `conserveth-e heat absorbed by said housing and is intended to cover all of said housing -1 which is not exposed to the light -Which strikes it when said light is vprojected through lens 3: said light is projected through lens 3, in the direction of the arrow A Fig. 2. The part of' thel lens housing '1 and the ring 4 that comes injcontact WithV the edge of lens 3 is preferably shaped to therein, as. and for tained thereln, as and for the purpose herein the sanie radius as the lens 3 so as to insure good, Contact surface for -the heat to pass and repasfs from lens 3 to lens housing 1.

Many variations may beniade in the form of this device from that settorth, without departing from the scope ,of the invention. Thus, any suitable means mai7 Abe'used to keep a constant pressure of the lens 3 to the 'housing 1 than that' here show-n, also,

a diii'erent means of retaining the lens 3-'i'n the .housing 1 .than that shown may be used. The lens housing` 1l may be attached in any .suitable ina'nner to the machine in'which' it is to be used. The. heat insulating material 2 may in certain lcases be dispensed' Having. thus fully described my invention,

what I claim is- 1. A lens temperature equalizer'compris-- ing a. heat absorbing lens housing, said lens housing consisting of sutticient volume to absorb heat from. and impart heat .to 'thel peripheral portions of a lens' containedI the purpose 4'herein set forth. 2. A lens temperatureequalizer lcomprising aheat absorbing lens housing, said lens housing providing for lens retention, and said lens housing consisting of suiiicient volume'to absorb heat from and impart heat to the peripheral portions of a lens con.-

set forth.

3. -A lens temperature equalizer {comprising a heat absorbing l'e'n's 'housing,said lensv housing providing for lens retention, said lens retention being expansive, and contract-ive, and said lens housingV consisting of' sutlicient volume to absorb heat from and impart heat to .the peripheral portions of a lens contained therein, as and for the purpose herein set forth.

4. A lens temperature equalizer comprising a heat absorbing lens housing, said lens housing having a duct through the same.

said duct providing for lens retention` and said lens housing Aconsisting of sufficient volume to absorb heat from and impart heat tions of 'a lens contained therein, as and for to the `:peripheral portionsl of a lensconset forth.

5. -A lens temperature equalizer compris'-v ing a heat labsorbing lens housing, said lens housing having a ductthro'ugh the saine, said lens housing consisting of sutlci'cmt` .volume to absorb" 'heat' from .and impart heat to the-.peripheral portions of a lens tained therem, as and for the purpose herein contained therein,.;as and for the .purpose herein'set forth. 6. A lens temperature equalizer comprising .a heat absorbing` lens housing,said lens housing having a duct through the same,

lsaid duct containing inwardand outwardA lens limiting projections, said projections conforming to the curvature of lens contained therein, and said lens housing consisting of suicient volume to absorb heat from and impart heat to the peripheral porthe purpose herein set forth.

'-7. A lens 'temperature' equalizerl comprising a heat absorbing lenshousing, said lens housing having 4`a -duct through the same, said duct containing inward and outward lens' limiting projections, said projections being expansive and"contra'ctive, and said lens housing consisting of sufficient volume to absorb heat from and impart heat to the peripheral. portions of a lens contained therein, ,as and for the purpose herein set forth. y

8. A lenstemperature equalizer comprising a .heat absorbing lens housing, said lens' housing having a duct through the same, said duct containing inward 'and outward lens limiting'projections, saidprojections beino' expansive and contractive and conforming to the curvature of lens'contained` therein, and said lenshousing consisting of'sutlicient volurne to absorb .heat from and impart heat to the.peripheralportions offa'lens contained therein, as andor-th'e p urpo here- .in set forth'- 

